COMPARISON OF TRANSILLUMINATION AND HISTOLOGIC SLIDE MEASUREMENTS OF CHOROIDAL MELANOMA

Objective: To compare transillumination and histologic slide measureme nts of choroidal melanomas in 479 eyes randomized to enucleation in th e Collaborative Ocular Melanoma Study. Design: Transillumination defec ts were measured during gross examination of enucleated eyes. Tumor ba sal diameter and height were measured on histologic slides and each tu mor was assigned to 1 of 8 distinct shape categories. Comparison of th e transillumination and histologic slide measurements revealed 3 categ ories of difference: underestimation (transillumination measurement mo re than 4 mm smaller than the histologic slide measurement), overestim ation (transillumination measurement more than 4 mm larger than the hi stologic slide measurement), and agreement within 4 mm. Results: There was good correlation between transillumination and histologic slide e stimates of largest basal diameter, particularly when the basal diamet er was 16 mm or less, Measurement discrepancies were related to the sh ape of the tumors but not to the presence of sub-retinal fluid or fixa tion. Conclusion: Agreement was high between measurements of transillu mination defect and histologic sections.